Firearms with barrels that are removable without the need to use special barrel changing equipment such as a barrel wrench and a barrel vise have been in use for a number of years. Sporting firearms with this feature, such as take down firearms, have been popular since they allow a firearm to be broken down into two relatively small packages for transportation purposes and then be readily assembled by the shooter when it is desired to use the firearm. Unfortunately, this type of firearm requires that the receiver and the barrel of the firearm be designed with take down features and this increases the complexity of the firearm. Also, in many cases firearms with this take down feature are not as accurate as rigid firearms without this feature.
Systems that will permit the barrel to be changed have been used in the past for machine guns in an attempt to take care of the barrel heating problem caused by the rapid firing of cartridges in the machine gun barrel. When a cartridge is fired in a firearm barrel powder is burned and this produces heat that is partly transferred to the firearm barrel. With a non-automatic type firearm, sufficient time exists between shots that this heat is partially dissipated and hence heating of the firearm barrel is not a problem. However, with an automatic weapon there is insufficient time between shots for the heat to be dissipated and hence the amount of heat build up in the barrel can cause the barrel to become too hot for the proper functioning of the weapon. Such barrel changing systems for machine guns have required that the machine gun be specifically designed with this barrel change feature and that the receiver be designed for this feature. This of course increases the complexity of the firearm. Both this barrel change system and the previously mentioned take down system use the same configuration of barrels and associated equipment.
In many instances it is highly desirable to have a firearm that can readily utilize different types of barrels. This is particularly true of military type firearms since they can be used in different situations where a different type of barrel would be necessary or desirable. For instance, for accurate long range shooting a relatively long heavy barrel would be desirable and a short light weight barrel would be desirable for close range shooting in a confined area. Many barrels came with provisions for attaching additional equipment such as a wide variety of sights, grenade launchers, etc. and it is desirable to change barrels to mount barrels that already have particular types of equipment to the receivers rather:.than having to mount the equipment to the barrel.
While it is possible to make such barrel changes, it can not normally be done at the using unit level since special barrel changing equipment is necessary. In addition, in the case of the U.S. Military M-16 type weapon, barrel changes can damage the aluminum receiver of the firearm. Consequently, frequent barrel changes of the M-16 type weapons should be avoided.
Consequently, although there have been barrel change firearm systems in the past such as the take down firearms and the machine gun barrel change systems, these have not been useful in providing a barrel change system that readily permits one receiver that has no barrel change provisions to be used with a variety of different types of barrels and equipment attached to the barrels.
This invention relates to firearms with changeable barrels and more particularly to firearms with readily changeable barrels.
Accordingly, it is an object of the invention to provide firearm barrel change apparatus that increases the effectiveness of the firearm.
It is an object of the invention to provide firearm barrel change apparatus that permits the firearm to be used in a variety of roles.
It is an object of the invention to provide firearm barrel change apparatus that permits one firearm to be used with a variety of different types of barrels.
It is an object of the invention to provide firearm barrel change apparatus that permits one firearm to be used with a variety of different types of barrels and attached equipment.
It is an object of the invention to provide firearm barrel change apparatus that permits one firearm to be used with a variety of different types of barrels and attached equipment without removing the equipment from the barrel.
It is an object of the invention to provide firearm barrel change apparatus that requires no modification to the basic firearm.
It is an object of the invention to provide firearm barrel change apparatus that uses a standard receiver.
It is an object of the invention to provide firearm barrel change apparatus that uses standard barrels.
It is an object of the invention to provide firearm barrel change apparatus that can be used to retrofit standard firearms.
It is an object of the invention to provide firearm barrel change apparatus that is easy to use to retrofit standard firearms.
It is an object of the invention to provide firearm barrel change apparatus that avoids damaging the receiver.
It is an object of the invention to provide firearm barrel change apparatus that avoids possible damage to firearms with aluminum receivers.
It is an object of the invention to provide firearm barrel change apparatus that maintains the accuracy of the firearm when the barrel is changed.
It is an object of the invention to provide firearm barrel change apparatus that does not require the removal of the handguard in order to change the barrel.
It is an object of the invention to provide firearm barrel change apparatus that uses a handguard that allows access to remove the barrel from the receiver.
It is an object of the invention to provide firearm barrel change apparatus that uses a handguard that only touches the barrel at its breech end.
It is an object of the invention to provide firearm barrel change apparatus that permits barrels to be changed without special tools.
It is an object of the invention to provide firearm barrel change apparatus for military use that permits barrels to be readily changed at the local unit level.
It is an object of the invention to provide firearm barrel change apparatus that is easy to use by the person using the firearm.
It is an object of the invention to provide firearm barrel change apparatus that requires very little training to use.
It is an object of the invention to provide firearm barrel change apparatus that is simple in its operation.
It is an object of the invention to provide firearm barrel change apparatus that has few parts.
It is an object of the invention to provide firearm barrel change apparatus that can be manufactured with the use of altered existing parts.
It is an object of the invention to provide firearm barrel change apparatus that is particularly useful with firearms having aluminum receivers.
It is an object of the invention to provide firearm barrel change apparatus that is particularly useful with firearms in which the surfaces for the bolt locking lugs are not part of the receiver.
It is an object of the invention to provide firearm barrel change apparatus that is particularly useful for firearms that use firearm barrels where the surfaces for the bolt locking lugs are attached to or form part of the barrel structure.
It is an object of the invention to provide firearm barrel change apparatus that is particularly useful with the M16 type firearms.
These and other objects of the invention will become apparent from the following described firearm barrel change apparatus for a firearm having a receiver and a barrel with a portion configured to slide into the receiver. The firearm barrel change apparatus includes a barrel receiving nut having provisions for slidably receiving a barrel retention member and a barrel retention member having a portion thereof sized and shaped to cooperate with said barrel receiving nut to lock the barrel to the receiver. A special handguard assembly is also provided that allows the barrel retention member to be used with the barrel receiving nut without removing the handguard assembly. A handguard extension assembly is also provided that can be added to the handguard assembly when longer barrels are attached to the receiver.